In the cleaning industry, a solvent such as a cleaning fluid remaining in a cleaned object (dried object) may not only become a source origin of the volatile organic compound (VOC) to worsen a working environment, but also cause a chemical burn when wearing the cleaned object. Therefore, cleaned objects are sufficiently dried, and classified.
In a case of a drying apparatus not with a vaporized-solvent-recovery function of volatized solvent, the solvent volatized from the cleaning object is exhausted outside. However, it is known that an emission volume of VOC can be restrained by using a drying apparatus with a vaporized-solvent-recovery function. Further, because the drying apparatus with a vaporized-solvent-recovery function recovers and reuses the solvent which has been discharged to the air, an amount of solvent usage and a cost are reduced. Therefore, the cleaning industry converts the drying apparatus into that with a vaporized-solvent-recovery function.
In such a drying apparatus with a vaporized-solvent-recovery function, the solvent is vaporized from the cleaned object with hot air, and the gasified solvent is cooled and liquefied with a cooler. Then, the liquefied gas is separated into the solvent and water with a water separator, and the solvent is recovered. Then, the solvent recovered by the drying apparatus with a recovery function is reused.
Patent Document 1 discloses a dry-cleaning machine which cools the vaporized solvent. This dry-cleaning machine uses a common freezing machine with respect to two coolers of a solvent cooler and a drying cooler to maintain the solvent at sufficiently low temperature with a low cost (for example, Japanese Published Patent Application No. 2003-311095).
As described above, in the cleaning industry, conventionally, due to cooling the solvent, a discharge amount of VOC is restrained and an amount of solvent usage is reduced. However, in a case that a limonene which is low cost, has low toxicity on the human body, and has bactericidal effects is used as the solvent, because a lemon-like odor of the limonene is remained in the cleaned object when the cleaning object is half dried, the drying time of the conventional drying apparatus with a vaporized-solvent-recovery function is sufficiently long for fully vaporizing the solvent.
Essentially, the drying time of the cleaned object such as clothes is varied according to the structure of the cleaned object. However, in the cleaning industry, various kinds of cleaned object are dried at once. Therefore, the cleaned object is generally dried too much, and may be damaged. Further, in a case that the solvent is limonene, because the limonene is flammable, the drying time cannot be long, so that the cleaned object may be half dried. In this case, there is a problem that the recovery rate of the solvent is reduced. Such a problem is not limited to the cleaning industry, but the overall drying apparatus in which the vaporized solvent is recovered in a drying operation.
Accordingly, an object of the present invention is to provide a drying apparatus with a vaporized-solvent-recovery function and a method for drying solvent recovery to be able to increase a recovery rate of a solvent and to reduce damage to a dried object caused by too much drying.